796 resultados para Halliday, Jon: Mao
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OBJECTIVE: Thiol isomerases facilitate protein folding in the endoplasmic reticulum, and several of these enzymes, including protein disulfide isomerase and ERp57, are mobilized to the surface of activated platelets, where they influence platelet aggregation, blood coagulation, and thrombus formation. In this study, we examined the synthesis and trafficking of thiol isomerases in megakaryocytes, determined their subcellular localization in platelets, and identified the cellular events responsible for their movement to the platelet surface on activation. APPROACH AND RESULTS: Immunofluorescence microscopy imaging was used to localize protein disulfide isomerase and ERp57 in murine and human megakaryocytes at various developmental stages. Immunofluorescence microscopy and subcellular fractionation analysis were used to localize these proteins in platelets to a compartment distinct from known secretory vesicles that overlaps with an inner cell-surface membrane region defined by the endoplasmic/sarcoplasmic reticulum proteins calnexin and sarco/endoplasmic reticulum calcium ATPase 3. Immunofluorescence microscopy and flow cytometry were used to monitor thiol isomerase mobilization in activated platelets in the presence and absence of actin polymerization (inhibited by latrunculin) and in the presence or absence of membrane fusion mediated by Munc13-4 (absent in platelets from Unc13dJinx mice). CONCLUSIONS: Platelet-borne thiol isomerases are trafficked independently of secretory granule contents in megakaryocytes and become concentrated in a subcellular compartment near the inner surface of the platelet outer membrane corresponding to the sarco/endoplasmic reticulum of these cells. Thiol isomerases are mobilized to the surface of activated platelets via a process that requires actin polymerization but not soluble N-ethylmaleimide-sensitive fusion protein attachment receptor/Munc13-4-dependent vesicular-plasma membrane fusion.
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In the mid-1990s the North Atlantic subpolar gyre warmed rapidly, which had important climate impacts, such as increased hurricane numbers, and changes to rainfall over Africa, Europe and North America. Evidence suggests that the warming was largely due to a strengthening of the ocean circulation, particularly the Atlantic Meridional Overturning Circulation (AMOC). Since the mid-1990s direct and indirect measurements have suggested a decline in the strength of the ocean circulation, which is expected to lead to a reduction in northward heat transport. Here we show that since 2005 a large volume of the upper North Atlantic Ocean has cooled significantly by approximately -0.45C or 1.5x10^22 J, reversing the previous warming trend. By analysing observations and a state-of-the-art climate model, we show that this cooling is consistent with a reduction in the strength of the ocean circulation and heat transport, linked to record low densities in the deep Labrador Sea. The low density in the deep Labrador Sea is primarily due to deep ocean warming since 1995, but a long-term freshening also played a role. The observed upper ocean cooling since 2005 is not consistent with the hypothesis that anthropogenic aerosols directly drive Atlantic temperatures.
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Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here we quantify the pattern and magnitude of diel temperature variability of surface waters using high-frequency data from 100 lakes. We show that the near-surface diel temperature range can be substantial in summer relative to long-term change and, for lakes smaller than 3 km2, increases sharply and predictably with decreasing lake area. Most small lakes included in this study experience average summer diel ranges in their near-surface temperatures of between 4 and 7°C. Large diel temperature fluctuations in the majority of lakes undoubtedly influence their structure, function and role in biogeochemical cycles, but the full implications remain largely unexplored.
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Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010-2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually supressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade.
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Alzheimer`s Disease (AD) is the most common type of dementia among the elderly, with devastating consequences for the patient, their relatives, and caregivers. More than 300 genetic polymorphisms have been involved with AD, demonstrating that this condition is polygenic and with a complex pattern of inheritance. This paper aims to report and compare the results of AD genetics studies in case-control and familial analysis performed in Brazil since our first publication, 10 years ago. They include the following genes/markers: Apolipoprotein E (APOE), 5-hidroxytryptamine transporter length polymorphic region (5-HTTLPR), brain-derived neurotrophin factor (BDNF), monoamine oxidase A (MAO-A), and two simple-sequence tandem repeat polymorphisms (DXS1047 and D10S1423). Previously unpublished data of the interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta) genes are reported here briefly. Results from others Brazilian studies with AD patients are also reported at this short review. Four local families studied with various markers at the chromosome 21, 19, 14, and 1 are briefly reported for the first time. The importance of studying DNA samples from Brazil is highlighted because of the uniqueness of its population, which presents both intense ethnical miscegenation, mainly at the east coast, but also clusters with high inbreeding rates in rural areas at the countryside. We discuss the current stage of extending these studies using high-throughput methods of large-scale genotyping, such as single nucleotide polymorphism microarrays, associated with bioinformatics tools that allow the analysis of such extensive number of genetics variables, with different levels of penetrance. There is still a long way between the huge amount of data gathered so far and the actual application toward the full understanding of AD, but the final goal is to develop precise tools for diagnosis and prognosis, creating new strategies for better treatments based on genetic profile.
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A real-time polymerase chain reaction (PCR) test was developed on the basis of the Leishmania glucose-6-phosphate dehydrogenase locus that enables identification and quantification of parasites. Using two independent pairs of primers in SYBR-Green assays, the test identified etiologic agents of cutaneous leishmaniasis belonging to both subgenera, Leishmania (Viannia) and Leishmania (Leishmania) in the Americas. Furthermore, use of TaqMan probes enables distinction between L. (V.) braziliensis or L. (V.) peruviania from the other L. (Viannia) species. All assays were negative with DNA of related trypanosomatids, humans, and mice. The parasite burden was estimated by normalizing the number of organisms per total amount of DNA in the sample or per host glyceraldehyde-3-phosphate dehydrogenase copies. The real-time PCR assay for L. (Leishmania) subgenus showed a good linear correlation with quantification on the basis of a limiting dilution assay in experimentally infected mice. The test successfully identifies and quantifies Leishmania in human biopsy specimens and represents a new tool to study leishmaniasis.
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Using data taken by SELEX during the 1996-1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with Sigma(-), p, pi(-), and pi(+) beams. Parametrizing the dependence of the inclusive production cross section on the atomic number A as A(alpha), we determine alpha for D(+), D(0), D(s)(+), D(+)(2010), Lambda(+)(c), and their respective anti-particles, as a function of their transverse momentum p(t) and scaled longitudinal momentum x(F). Within our statistics there is no dependence of alpha on x(F) for any charm species for the interval 0.1 < x(F) < 1.0. The average value of alpha for charm production by pion beams is alpha(meson) = 0.850 +/- 0.028. This is somewhat larger than the corresponding average alpha(baryon) = 0.755 +/- 0.016 for charm production by baryon beams (Sigma(-), p).
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We report the first observation of two Cabibbo-suppressed ecay modes, Xi(+)(c) -> Sigma(+)pi(-)pi(+) and Xi c+ -> Sigma(-)pi(+)pi(+). We observe 59 +/- 14 over a background of 87, and 22 +/- 8 over a background of 13 events, respectively, for the signals. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 Gev/c Sigma(-) beam. The branching ratios of the decays relative to the Cabibbo-favored Xi c+ -> Xi(-)pi(+)pi(+) are measured to be B(Xi(+)(c) -> Sigma(+)pi(-)pi(+))/B(Xi(+)(c) -> Xi(-)pi(+)pi(+)) = 0.48 +/- 0.20, and B(Xi(+)(c) -> Sigma(-)pi(+)pi(+))/B(Xi(+)(c) -> Sigma(-)pi(+)pi(+)) = 0.18 +/- 0.09, respectively. We also report branching ratios for the same decay modes of the Delta(+)(c) relative to Delta(+)(c) -> pK(-)pi(+.) (C) 2008 Elsevier B.V. All rights reserved.
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PHENIX has measured the electron-positron pair mass spectrum from 0 to 8 GeV/c(2) in p + p collisions at root s = 200 GeV. The contributions from light meson decays to e(+)e(-) pairs have been determined based on measurements of hadron production cross sections by PHENIX. Within the systematic uncertainty of similar to 20% they account for all e(+)e(-) pairs in the mass region below similar to 1 GeV/c(2). The e(+)e(-) pair yield remaining after subtracting these contributions is dominated by semileptonic decays of charmed hadrons correlated through flavor conservation. Using the spectral shape predicted by PYTHIA, we estimate the charm production cross section to be 544 +/- 39(stat) +/- 142(syst) +/- 200(model) pb. which is consistent with QCD calculations and measurements of single leptons by PHENIX. (C) 2008 Elsevier BV. All rights reserved.
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Detta examensarbete har utförts på SSAB- Tunnplåt i Borlänge under vårterminen 2004 och omfattar 10 veckors arbete.SSAB sköter idag sin kommunikation med distributionslagren via fax, telefon eller e-post. Eftersom detta är ett ganska tidskrävande kommunikationssätt, vill SSAB ha en smidigare och snabbare kommunikationslösning. Den lösning som SSAB vill ha är en extern Web-service-lösning för att upprätta en säker kommunikation med sina distributionslager.Parallellt med byggandet av Web-service-lösningen arbetades en förvaltningsmodell fram. Den beskriver hur förvaltningsorganisationen med dess rutiner kan se ut vid implementering av lösningen.För att skapa en säker förbindelse med Web-servicen skall en webbklient användas som i sin tur anropar en COM+ komponent. Detta för att kunna skicka med certifikatet ifrån webbklienten till webbservern där Web-servicen ligger. COM+ komponenten måste få tillgång till en användarprofil när den kommunicerar med Web-servicen. Detta för att kunna upprätta en SSL-förbindelse i det inledande skedet. SSL-förbindelsen skall läggas i den VPN-tunnel som mVPN tillhandahåller via WSSAL.
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För att visa på nyttan av vad ett användartest kan erbjuda i samband med utveckling av en webbplats har vi i denna rapport tagit med alla stegen fram till och med utveckling i Vattenfallsmetoden, som är den metod som vi använt oss av. De föregående stegen i metoden är förstudie, analys och design. Förstudien valde vi att genomföra som ett användartest för att få fram vad användarna verkligen efterfrågade. Vi analyserade sedan resultatet av användartestet och gjorde en sammanfattning, men i den tog vi även hänsyn till det material som vi samlat in och vad de ansvariga på Hedlunds Hus AB efterfrågade. Detta resulterade i en lista med prioriterade funktioner och innehåll, som vi sedan utgick ifrån vid utveckling av webbplatsen. Vid utveckling av webbplatsen togs även hänsyn till det material som vi samlat in om webbutformning/design. Att använda sig av ett användartest i förstudiefasen tycker vi är ett bra sätt för att få fram vad användarna efterlyser och inte vad vi som webbutvecklare själva tror att användarna behöver.
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När en grafisk profil för en spännande ny internationell webbtidning för ungdomar skall göras är det viktigt att tänka på hur färg och form påverkar våra känslor. Experiment med färg som har gjorts av ledande färgpsykologer och färgvetare som Goethe, Itten, Lüscher och Karl Ryberg bevisar att färg har en stor psykologisk påverkan på människan. Internet är ett väldigt effektiv kommunikationsmedium och för att kommunicera effektivt är det inte bara orden, utan även färgerna och formerna på webbsidorna som skall vara väl genomtänkta. Vilka färger kopplar ungdomar i Sverige och Chile ihop med vissa känslor? Vilka former kopplas ihop med samma känslor? Svaren på de frågorna sammanställdes och analyserades efter svaren på en enkät om färg och form som delades it till två högstadieskolor i Borlänge, Sverige och en i Santiago, Chile.
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The government appointed in 2004 a special investigator with the objective to investigate the possibility of introducing a new law concerning implementation of obligatory cash registers with certain certification. This resulted in SOU 2005:35 ”Krav på kassaregister - Effektivare utredning av skattebrott” (Proposition 2006/07: 105). Following advice received from the respondents, the government has drafted a bill submitted to parliament in March 2007. Government bill 2006/07: 105 proposals for new law on cash registers, and submitted to parliament 2007th Act (2007:592) on the cash register was adopted by parliament in March that year and came into force on 1 January 2010. Earlier great opportunities for tax cheating has been available by various methods so as to simply not punch in a sale at the checkout, use the training function type, use receipt copies, manipulate register functions on its program level, using alternative programming etc. These opportunities are eliminated in the certified cash registers. Respondent traders believed the most part has not changed the competition or that the change will be relatively small. They also thought it was too early to see any change at this time. A tendency among traders we have asked is that they feel negatively for the costs it imposes, with the new registry and that they are skeptical about the expected impact of the law, among others due to the scarce resources spent on follow-up. The Swedish tax agency is responsible for control and the new systems make it easier for Tax control, but actual physical on-scene control must be performed to detect irregularities.
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Undersökningens avsikt var att vinna kunskap om hur gymnasielärare förhåller sig till lanseringen av begreppet entreprenörskap i skolan. Uppsatsen klarlägger och systematiserar hur lärare beskriver innehållet i begreppen entreprenörskap och entreprenöriellt lärande och fördjupar sig även i hur lärarna ser på upprinnelsen till begreppens lansering i den svenska skolan. Undersökningen gör även en analys av möjliga entreprenöriella undervisningsmetoder samt de olika undervisningsrelaterade problem som lärarna anser att dessa metoder kan ge upphov till. Åtta kvalitativa intervjuer genomförda på en gymnasieskola i norra Sverige utgör basen för undersökningen. Studien nyttjar en abduktiv förståelseansats vilket betyder att analysen av det empiriska materialet kännetecknades av en pendelrörelse mellan en induktiv ansats och en deduktiv ansats. I arbetets resultatdel slås bland annat fast att begreppet entreprenöriellt lärande av lärarna ses som ett verktyg för undervisning i entreprenörskap. Det framgår även som tydligt att entreprenörskap främst sätts i samband med företagande och/eller kreativitet. Begreppet entreprenöriellt lärande uppfattas i sin tur som mer diffust och mindre värdeladdat än begreppet entreprenörskap. De undervisningsmetoder som lärarna ansåg vara förknippade med entreprenörskap betonade främst antingen undervisningsstrategier/undervisningsinnehåll eller undervisningsstruktur/undervisningsform. Med utgångspunkt i intervjupersonernas svar var det möjligt att klargöra att entreprenörskap, utifrån ett skolperspektiv, inte bör ses som något nytt. Samtliga lärare i undersökning utgick från redan befintliga tillvägagångssätt när de beskrev metoder för entreprenöriell undervisning. I och med att lärarna uppfattade att svagare elever, som av olika anledningar ofta kan ha svårare att finna kreativitet och initiativförmåga, som de elever som har svårast med den typ av undervisning som lärarna sätter i samband med entreprenörskap, klargör uppsatsen även att det är svagare elever som får störst problem med entreprenörskapsundervisning. De problem som lärarna ansåg att entreprenöriell undervisning kan resultera i sträckte sig sammantaget från elevorienterade problem till lärar- och skolorienterade problem. Allt som allt uppfattar lärarna att det är partipolitiska beslut och en övergripande samhällsutveckling som legat till grund för lanserandet av entreprenörskap i den svenska skolan. Denna slutsats sätter uppsatsen i samband med övergripande samhällsteoretiska uppslag av Manuel Castells och Richard Florida.